Hydraulic packings



Jan. 14, 1958 T. F. WATSON ETAL 2,819,917

' HYDRAULIC PACKINGS Filed Nov. 14, 1955 2 Sheets-Sheet 1 I ATTORNEYJan. 14, 1958 T. F. WATSON ET AL. 2,819,917

HYDRAULIC PACKINGS 2 Sheets-Sheet 2 Filed Nov. 14, 1955 A TTORNE) UnitedStates Fatent HYDRAULIC .PACKINGS Thomas Frank Watson, William Thomas-Tank,-and'Ccil Henry Bonsey, Waking, England assignors to James Walkerand Company Limited, Surrey, England, a corporation ofGreatBritainApplication November 14, 1955, Serial No. 546,614

Claims priority, application Great Britain October 25, 1955 4 Claims.(Cl. 286-26) This invention-relates to hydraulic packings for use in'making fluid tight joints in hydraulic machinery, for example; aroundthe ram or piston of a hydraulic press,

of the kind which consists in a header ring adapted to maintain the lipsof a U-shape or other suitable sealing member incontact with thesurfaces to be sealed, said header ring being adapted so that in use itis spring loaded by means of a number of coil springs which aremaintained permanently in position on the header ring bymeans of headedpins having shanks which are slidable in holes in the header ringandwhich form mountings for the springs which at one end bear against theundersides of the heads of the pins and at the opposite ends against thebottoms of recesses or drillings in the header ring.

Packings of the above kind as previously proposed.

comprised pins having elongated shanks that extended beyond theunderside of theheader ring and into the gap between the lips of thesealing member when the springs are compressed said pins being preventedfrom becoming sufiiciently wide and deep as to be able to receive the,

peened over ends of the shanks of the'spring retaining pins when fullyloaded. A further disadvantage resides in the fact that the peeningoverof the shanks of the pins had to be effected with the pins in positionin the header ring and with each spring compressed to cause the shanksto project to their full extent beyond the underside of the header ring.Unless exceptional care was taken the hammering necessary to effectpeening caused the unsupported part of the shank of each pin protrudingbeyond the header ring to bend and require either its replacement'orcorrection.

The object of the present invention is to avoid the above disadvantagesand this is effected by a construction which enables each pin and itsspring to be assembled as a unit and for each said unit to be fittedinto a recess in the header ring and preferably so that when thus fittedthe units are incapable of falling out whilst the header ring is beinghandled.

Broadly the present invention consists of a spring unit to form with aheader ring a spring loaded packing said unit comprising a headed pin, acoil spring mounted on the shank of the pin and an annular spring pad onthe outer end of the shank of the pin, the central hole in said springpad permitting said shank to slide through it and said spring padforming a seating for the spring said spring pad and the spring beingmaintained in position on the shank of the pin to form a unitarystructure by an enlargement on the outer end of the said shank which isformed after the spring and its pad have been assembled on the shank ofthe pin.

In a spring unit as above according to a preferred embodiment of thepresent invention the spring is held under slight compression betweenthe head of the pin-at one end and the spring pad at the opposite endand-said spring pad-is in-the form of a dished annular washer-having aperipheral diameter slightly greater than the internal diametcr of therecesses in the header ring-whereby on fitting the spring units into theheader ring-eachsaid unit requires to be pressed firmly down to thebottomofeach By this means the tendency of each spring pad to expandwill prevent the units from falling out when-therecess.

packing is being handled.

In this preferred embodiment the enlargement on the inner end of thepins shank will just enter the concentrichole which is drilled throughthe headerring from'the bottom of each recess and will be free to'slidedownand' up in the hole as the pin is depressed and released. The

shanks of the pins may thus be of such a length thateven when fullydepressed their outer ends need never-protrudebeyond the depth of theheader ring.

The enlargement at the outer end of each pin shank is made after thespring pad is pushed-into position over'the' freeend of the shank andthis may be effectedeither-by peening or by pinching in the sides of theshank on opposite sides to cause the metal to displace laterally.

Where the material composing the header ring issufii ciently hard thereis no need to line the recessesto'take the spring units but if thematerial is comparatively-soft it is advisable to fit a metal or'otherhard liner into each recess;

These may be provided by making the spring pads in theform of deep cupsor ferrules or-theymay be constructed as separate liners adapted toreceive spring units having theaforesaid shallow dish form of springpad.

With means according to the present invention the resistance to loadafforded by the spring units is dependent upon the depth of the recessesas it is preferredtomass produce the spring units wherebythe dimensionsof the units for each header will be substantially identical; and

by forming theenlargement at the inner end of each pin shank by pinchingin its sides therewill be no'risk-of the shanks bending during theoperation.

In order that the invention maybe clearly'understood and carried intoefiect a practical embodimentof "the spring units according tothe'em-bodirnent in which" the spring-pad is-in the form ofa-dishedannular washer;

Fig. 4 is a view similar to Fig. 3 showing a spring unit in which thespring pad is in the form of a split ferrule adapted to be pressed intoa recess in the header ring until its upper edge is flush with the upperface of the header ring.

Fig. 5 is a view similar to Fig. 4 showing a modified form of springunit in which the spring pad is in the form of a shouldered ferruleadapted to be pressed into a recess in the header ring until theshoulder of the upper end of the ferrule is hard against the upper faceof the header ring.

The hydraulic packing shown in Figs. 1 and 2 of the drawings consists ofa header ring and a sealing member 2, both of which are constructed inthe conventional form of packings of this type. The sealing member 2 ismoulded in rubber or other suitable sealing material with peripheralsealing lips 3 which are maintained in sealing contact with the surfacesof the stufiing box 4 and 3 shaft 5 by the sloping sides of theunderface 6 of the header ring.

To permit the free passage of pressure liquid to the cavity between thesealing lips 3 the header ring is provided with a continuous groove 7 inthe upper face of the ring, transverse slots 8 to permit the oil toenter groove 7 and holes 9 serving to convey the oil from the groove 7to the aforesaid cavity between the sealing lips 3.

For the purposes of the present invention the header ring is providedwith a further series of holes 10 which are counterbored at their upperor outer ends to provide recesses 11 for the reception of the springunits of the present invention.

Each spring unit of the present invention in its simplest form as shownin Fig. 3 consists in a pin 12 having a fiat head 13 at its outer end acoil spring 14 mounted on the shank of the pin and held in partialcompression between the underside of the head 13 and an annular springpad 15.

The central hole in the spring pad permits the shank of the pin 12 toslide through it and the spring pad is prevented from falling Off theend of the pin by the formation of an enlargement 16 on said end of thepin, said enlargement being formed by peening or pinching in the sidesof the shank of the pin after the spring 14 and its pad 15 have beenpositioned. There is thus provided a unitary structure the components ofwhich will always remain in assembled relationship.

The spring pad 15 in this embodiment is in the form of a shallow dishedwasher the peripheral diameter of which is greater than the internaldiameter of the recess 11 into which the unit is to fit so that infitting the spring units in the header ring each unit requires to bepressed firmly into its recess. By this means the tendency of eachspring pad to expand will prevent the units from falling out of therecesses when the packing is being handled.

The diameter or greatest width of the enlargements 16 and the diameterof the holes 10 is such that each pin is free to slide relative to andthrough its spring pad as the pin is depressed and released resultingfrom the application of pressure on the head 13 at its upper or outerend.

Where the material composing the header ring is sufficiently hard thereis no need to line the recesses 11 but where a lining is required thismay be provided as separate liners in the form of deep cups or ferrules.Alternatively the spring pads may be in the form of deep cups orferrules so as themselves to act as liners. Examples of these are shownin Figs. 4 and 5. In Fig. 4 the spring pad is in the form of a splitferrule 17 having straight sides integral with a base which has a holein it that permits the shank of the pin to slide in it but prevents theenlargement 16 from being drawn through. In assembling such a unit in aheader ring the same is pressed home until the base of the ferrule 17 isforced against the bottom of its recess.

For the fiat heads 13 in a complete assembly of spring units to besubstantially level it is therefore necessary that care is exercised inboring or drilling the recesses 11 to an even depth. To avoid thenecessity for this accuracy the spring unit shown in Fig. 5 is used.This differs from the unit shown in Fig. 4 by the formation of ashoulder 18 around the upper edge of its ferrule 17. This shoulder, whenthe unit is pressed home in its recess in the header ring seats againstthe upper face of the header ring and thus limits the depth to which theferrule can be pressed into a recess. Provided, therefore that therecesses are deep enough their depth may vary without affecting thelevel of the heads 13 of the pins in a complete assembly of units asthese must all be substantially at the same level.

We claim:

1. Mechanism for spring'loading a sealing packing comprising a headerring having a plurality of bored and counterbored openings with ashoulder therebetweeu, and an annular sealing member engaged by saidheader ring and adapted to contact the surfaces to be sealed; saidmechanism comprising, a plurality of pin elements each provided with ahead portion dimensioned to slide in the counterbored opening and with ashank portion, a plurality of resilient annular pads each received abovethe shoulder and urged against the surface of the counterbored opening,each of said shank portions extending through the hole of one of saidannular pads, and a plurality of springs each abutting one of said headportions and one of said annular pads to spring-load said header ringand said pin elements, each of said springs projecting above one of saidannular pads, and an enlarged extension provided at the free end of eachof said shank portions and larger than the hole of the corresponding ofsaid annular pads, said enlarged extensions sliding in said boredopenings, whereby each of said annular pads is secured to said headerelement and each of said pin elements is secured to one of said annularpads.

2. Mechanism constructed according to claim 1, wherever the resilientannular pads are dished annular washers.

3. Mechanism constructed according to claim 1, wherein each of saidshank portions is provided with a length at most equal to the length ofeach of said bored and counterbored openings, whereby under maximum loadsaid shank portions remain within said bored openings.

4. Mechanism constructed according to claim 3, wherein the resilientannular pads are dished annular washers.

References Cited in the file of this patent UNITED STATES PATENTS1,802,552 Corcoran Apr. 28, 1931 2,524,462 Miller et al. Oct. 3, 1950FOREIGN PATENTS 618,970 Great Britain Mar. 12, 1949

